The present invention relates to mattress or cushion structures designed to improve pressure distribution while reducing the overall thickness of the mattress or cushion. The mattress or cushion structures of the present invention illustratively include a foam base on which one or more indented fiber layers or other three dimensional engineered material are placed. The base and the three dimensional engineered material layers are illustratively encased in a cover to provide a mattress or cushion.
While the use of foam in mattresses and cushions is known and the use of three dimensional engineered material is known, the present invention relates to a unique combination of a foam base and three dimensional engineered material layers placed on the foam base. The present invention also contemplates that, in addition to the foam base, an air cushion layer may be used with the foam and the indented fiber layers to further enhance the pressure distribution capabilities of the mattress or cushion. In some embodiments, the base may be primarily, if not solely, an air cushion which is enhanced by at least one three dimensional engineered material layer. In other embodiments, water filled bladders, springs, or zones filled with beads, gel or other such material may be used in the base.
Reference is made to U.S. Pat. Nos. 5,731,062 and 5,454,142 disclosing the three dimensional fiber networks made from textile fabrics that have projections and optional depressions which are compressible and return to their original shape after being depressed. U.S. Pat. Nos. 5,731,062 and 5,454,142 are owned by Hoechst Celanese Corporation, Somerville, N.J. Such material is a synthetic thermoplastic fiber network in flexible sheets having projections and/or indentations for use as cushions and/or impact-absorbing components. The descriptions of such patents arc incorporated herein by reference to establish the nature of one example of three dimensional engineered material or indented fiber layer disclosed herein. It will be appreciated, however, that the present invention contemplates use of such layers whether or not they are supplied by Hoechst Celanese Corporation and whether or not they arc similar to the SPACENET.RTM. product.
It is understood that other types of materials similar to the SPACENET.RTM. material may be used. For example, the material may be any type of three dimensional engineered material having a spring rate in both the X and Y axes. Preferably such material is open and breathable to provide air passage through the layer. For instance, Model No. 5875, 5886, 5898, and 5882 materials from Muller Textile, a molded thermoplastic spacer matrix material available from Akzo Nobel, or other suitable material may be used. Therefore, the term "three dimensional engineered material" is meant to include any of these types of materials used in accordance with the present invention.
The concept is to use three dimensional fiber layer networks made from textile fibers that have projections and optional depressions or other structures which are compressible and which return to their original shapes after being compressed or the equivalents of such layers. The SPACENET.RTM. fiber networks are typically made by thermo-mechanical deformation of textile fabrics that arc in turn made from thermoplastic fibers. In accordance with the present invention other types of layers with individual spring or spring-like protrusions may be used.
It has been found that two or more such layers, hereinafter referred to as "indented fiber layers" for convenience will assist in the pressure distribution when incorporated into an assembly comprising a well designed support base which may comprise foam or some combination of foam and air. The SPACENET.RTM. layers are examples of such "indented fiber layers."
In the fabrication of a seat cushion, it has been found that improved pressure distribution is provided when the seat cushion is designed to form fit the buttocks of the person sitting on the cushion. When such seat cushions are used by patients who have experienced skin tissue breakdown on their buttocks, the improved pressure distribution will permit the patients to sit up in chairs for greater periods of time for the therapeutic value that accomplishes.
An apparatus of the present invention is therefore configured to support at least a portion of a body thereon. The apparatus includes a cover having an interior region, a base located within the interior region, and a three dimensional engineered material located within the interior region above the base. The three dimensional engineered material and the base cooperate to provide support for the body.
Additional features and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrated embodiments exemplifying the best mode of carrying out the invention as presently perceived.